Mathematical-Physical description of the oxygen-inhibited layer (OIL) in nanofilled dental polymers / Descripción físico-matemática de la capa inhibida por oxígeno en polímeros dentales nano rellenados

Abstract This research evaluates the presence of the oxygen-inhibited layer (OIL) on the top surface of a photopolymerized dental composite resin protected with a glycerin layer. This evaluation was conducted using physical and mathematical methods. Polymerized discs were fabricated to evaluate Vickers microhardness (VHN), and pre-and post-polymerized samples were used for the calculation of C-O/C-H ratios through Fourier Transform Infrared Spectroscopy (FTIR) (n=10), using two types of glycerin, one for medical use (MG) and another for dental use (DG). Surface hardness decreased from MG to DG to CO, and the increase in C-O/C-H ratios decreased in the same order (p<0.05). Samples protected with medical and dental glycerin layers are harder and exhibit lower C-O/C-H bond ratios than the control group.

Resumen La presente investigación evalúa la presencia de la capa inhibida por oxígeno OIL en la última superficie fotocurada de una resina compuesta de uso odontológica que fue protegida con una capa de glicerina. Esta evaluación se hizo a partir de métodos físicos y matemáticos. Se fabricaron discos polimerizados para evaluar la microdureza Vickers (VHN) y pre y post polimerizados para el cálculo de tasas C-O/C-H por medio de Espectroscopía Infrarroja Transformada de Fourier (FTIR) (n=10) usando dos tipos de glicerina, una de uso médico (MG) y otra de uso dental (DG). La dureza superficial disminuyó de MG a DG a CO y el aumento de tasas C-O/C-H disminuyó en ese mismo orden (p<0,05). Las muestras protegidas con capas de glicerina médica y odontológica son más duras y presentan menos cantidad tasas de enlaces C-O/C-H que el grupo control.

Biomechanical and chemical behavior of various bioactive materials in class II restorations / Desempeño biomecánico y químico de diferentes materiales bioactivos en restauraciones clase II

The aim of this in vitro study was to evaluate the biomechanical and chemical behavior of various bioactive materials in class II MOD restorations. Forty- eight standardized class II MOD cavities were prepared in sound extracted human molar teeth. The specimens were divided into four groups according to the restorative material: Group 1 (Filtek™ Z350 XT), Group 2 (Biodentine™ as a liner, and then restored with Filtek™ Z350 XT), Group 3 (Cention N™), and Group 4 (Activa™ Bioactive-Restorative). The samples were tested for fracture resistance by subjecting them to a compressive load in a Universal testing Machine. The failure modes of each specimen were evaluated. The alkalinizing potential and calcium ion release of the materials were measured. SEM-EDAX analyses were also performed for all materials. Data were analyzed using ANOVA and post hoc Tukey test (p<0.05). Group 1 showed the higher fracture resistance (p<0.05). Group 3 had greater fracture resistance values but no statistical difference from Group 4. Biodentine™ showed greater biomineralization potential. Class II MOD restorations of Group 1 displayed the higher fracture resistance; however, it was highly associated with catastrophic failure. Conversely, Biodentine™ presented a more significant bioactivity potential, and its use, as in Group 2, promoted the most favorable failure mode.

El objetivo de este estudio, in vitro, fue evaluar el desempeño biomecánico y químico de varios materiales bioactivos en restauraciones clase II MOD. Se prepararon cuarenta y ocho cavidades clase II MOD estandarizadas en dientes molares humanos extraídos. Las muestras se dividieron en cuatro grupos según el material de restauración: Grupo 1 (Filtek™ Z350 XT), Grupo 2 (Biodentine™ como base y luego restaurado con Filtek™ Z350 XT), Grupo 3 (Cention N™) y Grupo 4 (Activa™ Bioactivo-Reparador). La prueba de resistencia a la fractura fue realizada en una máquina de ensayo universal Instron. Se evaluaron los modos de falla de cada espécimen. Se midió el pH y la liberación de iones de calcio de los materiales. Se realizaron análisis SEM-EDAX. Los datos se analizaron mediante ANOVA y la prueba post hoc de Tukey (p<0,05). El grupo 1 mostró la mayor resistencia a la fractura (p<0,05). El Grupo 3 tuvo mayores valores de resistencia a la fractura que el Grupo 4, pero sin diferencia estadística. Biodentine™ mostró un mayor potencial de biomineralización. Las restauraciones Clase II MOD del Grupo 1 mostraron la mayor resistencia a la fractura; sin embargo, estuvo altamente asociado con fallas irreparables. Por el contrario, Biodentine™ presentó un potencial de bioactividad más significativo y su uso, como en el Grupo 2, promovió el modo de falla más favorable.

Depth of cure, mechanical properties and morphology of dual-cure bulk-Fill composites / Profundidad de curado, propiedades mecánicas y morfología de resinas compuestas duales

This study evaluated selected structural and physical properties, such as degree of conversion (DC), Vickers hardness (VHN), and compression strength (CS), of three new dual-cure bulk-fill resin-based composites (RBCs; ACTIVA, HyperFIL, and Fill-Up) and compared them to those of a conventional RBC (Filtek Z250) at three clinically relevant depths. Samples (n=180) were prepared in three depths (2,4, and 6mm). Fourier-transform infrared spectroscopy (FTIR) analysis and VHN and CS tests were performed. The DC value was calculated by considering the relative change in the aliphatic C=C peaks. The fractured surfaces of representative samples were characterized using scanning electron microscopy (SEM). Data were statistically evaluated using two-way analysis of variance and post hoc Bonferroni tests (p<0.05). According to the VHN results, Filtek Z250 showed the highest bottom/top hardness ratio (97.94±1.01) at 2mm thickness and ACTIVA showed the lowest bottom/top hardness ratio (43.48±5.64) at 6mm thickness (p<0.001). According to the FTIR results, the DC decreased with increasing thickness in all materials (p<0.05). Filtek Z250 showed the highest (301±12.4 MPa) and ACTIVA exhibited the lowest (232±17.2 MPa) CS values at 2mm thickness (p<0.05). The lowest CS values were obtained for ACTIVA, and the highest values were obtained for Filtek Z250 for samples with thicknesses of 4 and 6mm, respectively (p<0.05). The structural features of restorative composites, such as the resin chemistry and filler type and content, and the operational parameters (i.e., material thickness and curing conditions) strongly affect crosslinking reactions and thus the DC, VHN, and CS values.

Este estudio evaluó propiedades físicas y estructurales, como el grado de conversión (DC), la dureza Vickers (VHN) y la resistencia a la compresión (CS), de tres nuevos compósitos a base de resina de curado dual tipo bulk (RBC; ACTIVA , HyperFIL y Fill-Up) y los comparó con los de una resina compuesta convencional (Filtek Z250) en tres profundidades clínicamente relevantes. Se prepararon muestras (n=180) en tres profundidades (2,4 y 6mm). Se realizaron análisis de espectroscopia infrarroja por transformada de Fourier (FTIR) y pruebas VHN y CS. El valor de DC se calculó considerando el cambio relativo en los picos alifáticos C=C. Las superficies fracturadas de muestras representativas se caracterizaron mediante microscopía electrónica de barrido (MEB). Los datos se evaluaron estadísticamente mediante análisis de varianza de dos vías y pruebas post hoc de Bonferroni (p<0,05). De acuerdo con los resultados de VHN, Filtek Z250 mostró la relación de dureza inferior/superior más alta (97,94±1,01) con un espesor de 2mm y ACTIVA mostró la relación de dureza inferior/superior más baja (43,48±5,64) con un espesor de 6mm (p<0,001). De acuerdo con los resultados de FTIR, la DC disminuyó al aumentar el espesor en todos los materiales (p<0,05). Filtek Z250 mostró los valores de CS más altos (301±12,4 MPa) y ACTIVA los más bajos (232±17,2 MPa) a 2mm de espesor (p<0,05). Los valores más bajos de CS se obtuvieron para ACTIVA y los valores más altos para Filtek Z250 para muestras con espesores de 4 y 6mm, respectivamente (p<0,05). Las características estructurales de las resinas compuestas de restauración, como la química; además del tipo y contenido del relleno, y los parámetros operativos (es decir, el espesor del material y las condiciones de curado) afectan en gran medida las reacciones de interacción química y, por lo tanto, los valores de DC, VHN y CS.

Influence of two natural cross-linkers on microtensile bond strength durability ­ An in vitro study / Influência de dois reticuladores naturais na durabilidade da resistência de união à microtração ­ Um estudo in vitro

Objective: to investigate the effect of two natural cross-linkers on microtensile bond strength (µTBS) and evaluate their influence on the durability of the resin dentin bonds. Material and Methods: the Moringa oleifera and Centella asiatica plant extracts were qualitatively tested with high-performance thin layer chromatography (HPTLC) for the presence of phenols. The phenolic content ranged from 27 to 30 gallic acid equivalents (GAE), µg/mg of dry weight. After etching, two concentrations (5% and 1%) of these two extracts were prepared and used as pretreatment liners on dentin. They were applied for a min. After restoration with resin composite, dentin resin beams were prepared. The study groups were 5% Moringa, 1% Moringa 5% Centella 1% Centella, and control (without cross-linker application). For each group, half of the samples underwent µTBS testing after 24 hours, while the remaining half were immersed in artificial saliva to assess the bond's longevity after 6 months of ageing. Statistical analysis was performed using one-way ANOVA followed by Tukey's post hoc test. Results: both 5% and 1% Moringa showed a significant difference (p<0.05) compared to the other groups at both intervals. However, after ageing, the specimens in the control and 1% Centella groups resulted in a significant decrease in µTBS. Conclusion: overall, both concentrations of Moringa (5% and 1%) were effective in stabilising the bond during both intervals.(AU)

Objetivo: investigar o efeito de dois reticuladores naturais na resistência de união (µTBS) à microtração e avaliar sua influência na durabilidade da adesão da resina à dentina. Material e Métodos: extratos das plantas Moringa oleifera e Centella asiatica foram qualitativamente testados através de cromatografia em camada fina de alta performance (HPTLC) para a presença de fenóis. O conteúdo fenólico alcançou entre 27 a 30 equivalentes de ácido gálico (GAE), µg/mg de peso seco. Após o condicionamento, duas concentrações (5% e 1%) dos extratos foram preparadas e utilizadas como forros de pré-tratamento em dentina. Eles foram aplicados por um minuto. Após a restauração com resina composta, palitos de dentina e resina foram preparados. Os grupos foram 5% Moringa, 1% Moringa, 5% Centella, 1% Centella e controle (sem aplicação de reticulador). Para cada grupo, metade das amostras foram submetidas ao teste µTBS após 24 horas, enquanto a outra metade foi imersa em saliva artificial para avaliar a longevidade adesiva após 6 meses de envelhecimento. Foi realizada análise estatística através de ANOVA 1-fator, seguido do teste post hoc de Tukey. Resultados: ambas as concentrações de 5% e 1% de Moringa demonstraram diferença significativa (p<0.05) comparadas aos outros grupos em ambos os intervalos. No entanto, após o envelhecimento, os espécimes dos geupos controle e 1% de Centella resultaram em uma redução significativa de µTBS. Conclusão: no geral, ambas as concentrações de Moringa (5% e 1%) foram efetivas em estabelecer a adesão em ambos os intervalos (AU)

Bond strength of bulk-fill resin composites: the effect of cavity preparation and aging

Aim: Evaluating the resin-dentin bond strength of Class II conventional and bulk-fill composite restorations, using different cavity sizes before and after aging. Methods: Seventy-five human molars were distributed into groups according to the buccolingual width of the cavities, conservative (n=25) and extended (n=50). They were divided according to the restorative material: conventional (Z100/control group) or bulk-fill resin composites (Filtek Bulk Fill/FBF; Tetric N Ceram Bulk Fill/TNCBF; Filtek Bulk Fill Flow/FBFF; Surefill SDR flow/SDR). The restored teeth were sectioned on sticks (n=50 per restorative materials + width cavities group), half were stored in Water/Ethanol 75% for 30 days and the other half were submitted to the immediate microtensile bond strength (µTBS) test. Data were analyzed applying the Three-Way Analysis of Variance (ANOVA), Bonferroni test, test t, and Weibull analyses (p<0.05). Results: SDR and FBF presented lower µTBSvalues for extended preparation when compared to the conservative preparation, before aging. After aging, only for the FBFF, a decrease in the µTBSvalues was observed. Comparing the µTBSvalues, before and after aging, the SDR demonstrated lower µTBSvalues after aging when the conservative cavity was used. A decrease in the µTBSvalues was observed for the Z100, the FBF and, the FBFF, after aging, when the extended cavity was used. Conclusion: The effect of cavity preparation and aging on the resin-dentin of Class II is material dependent. Most of the bulk-fill resin composites evaluated presented a similar performance to the conventional resin composites for all the conditions of this study

The effects of different antioxidant agents on the microtensile bond strength of composite resin to bleached Enamel / Efecto de diferentes agentes antioxidantes en la resistencia a la microtracción de la resina compuesta al esmalte blanqueado

Abstract The objective of this in vitro study is to examine the effect of antioxidants on the bonding strength of composite resin to bleached enamel. One hundred twenty non decay teeth were used in this study. Specimens were cut from the enamel cement junction. Then the specimens were randomly assigned into two groups-office bleaching and home bleaching. Bleaching antioxidants were applied to the first 12 subgroups. The specimens in the remaining 12 groups were kept in artificial saliva for 14 days and antioxidants were applied. Composite resin restoration was applied to all specimens. A cutting device was employed to obtain six specimens (0.9mm) from each tooth, and the microtensile bond strength (μTBS) test was performed. Data were analyzed using one-way ANOVA, the paired t-test, and Duncan's post hoc test (p=0.05). In office bleaching specimens, immediate antioxidant application increased the μTBS values (p0.05). Mean μTBS values in the groups to which antioxidants were applied two weeks after home bleaching were higher than those in the groups in which antioxidants were applied immediately. The use of antioxidants after bleaching may increase the MTBS value. The clinician should take this into account especially in immediate restoration applications after bleaching.

Resumen El objetivo de este estudio in vitro fue examinar el efecto de los antioxidantes sobre la resistência adhesiva de la resina compuesta al esmalte blanqueado. En este estudio se utilizaron ciento veinte dientes sin caries. Se cortaron especímenes a nivel de la unión esmalte-cemento. A continuación, los especímenes se asignaron aleatoriamente a dos grupos: blanqueamiento en el consultorio y blanqueamiento en casa. Se aplicaron antioxidantes de blanqueamiento a los primeros 12 subgrupos. Los especímenes de los 12 grupos restantes se mantuvieron en saliva artificial durante 14 días y se aplicaron antioxidantes. Se aplicó una resina compuesta a todos los especímenes empleando un dispositivo de corte para obtener seis especímenes (0,9mm) de cada diente, y se realizó la prueba de resistencia a la adhesión por microtensión (μTBS). Los datos se analizaron mediante un ANOVA de una vía, la prueba t pareada y la prueba post hoc de Duncan (p=0,05). En las muestras de blanqueamiento de oficina, la aplicación inmediata de antioxidantes aumentó los valores de μTBS (p0,05). Los valores medios de μTBS en los grupos a los que se aplicaron antioxidantes dos semanas después del blanqueo en casa fueron mayores que los de los grupos en los que se aplicaron antioxidantes inmediatamente. El uso de antioxidantes después del blanqueamiento puede aumentar el valor de μTBS. El clínico debe tenerlo en cuenta, especialmente en las aplicaciones de restauración inmediatas tras el blanqueamiento.

Pre-Heating effect on the microhardness and depth of cure of Bulk-Fill composite resins / Efecto del precalentamiento de las resinas compuestas Bulk-Fill en la microdureza y la profundidad de curado

Abstract The aim of this study was to investigate the effect of preheating three bulk-fill and one conventional composite resin on the Vickers microhardness and depth of cure of these composites. In this study, three bulk-fill composites- SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), and one conventional composite resin G-ænial POSTERIOR (GP) were used as the control group. The samples were obtained at room temperature (24°C) and at 55°C in T2 mode after being placed in a heating device for 10 minutes. The samples were divided into eight groups (n=10) according to the type of material and heating process that was utilized (preheated and nonheated). All samples were tested with a Vickers microhardness (VHN) tester on the bottom and top surfaces. The first measurements were obtained at baseline; the second set of measurements was performed after the samples were stored in distilled water at 37°C for 24 hours. The depth of cure was calculated using a bottom/top hardness ratio of measurements. Statistical analysis was performed utilizing the SPSS V23 and Shapiro-Wilk tests. Lastly, the Duncan test was used for multiple comparisons (p<0.05). While the VHN increased after the preheating procedure in bulk-fill composites, it decreased in GP. There was no difference between the baseline and the 24-hour VHN values in SDR and GP. After 24 hours, while the VHN of EST increased, the VHN of AFX decreased. There was no difference between the hardness ratios of the AFX and EST samples (p<0.001) and hardness ratios were greater than GP and SDR. When comparing the baseline and the 24- hour values, the VHN depended on the type of materials. Sufficient curing depth was obtained in all groups with a thickness of 2mm.

Resumen El objetivo fue investigar el efecto del precalentamiento de tres resinas Bulk-fill, una resina compuesta convencional sobre la microdureza Vickers y la profundidad de curado de estas resinas. Se utilizaron tres composites Bulk-Fill-SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), y una resina compuesta convencional G-ænial POSTERIOR (GP) como grupo de control. Las muestras se obtuvieron a temperatura ambiente (24°C) y a 55°C en modo T2 después de haber sido colocadas en un dispositivo de calentamiento durante 10 minutos. Se dividieron en ocho grupos (n=10) según el tipo de material y el proceso de calentamiento que se utilizó (precalentado y no calentado). Se probaron con un medidor de microdureza Vickers (VHN) en las superficies inferior y superior. Las primeras mediciones se obtuvieron en la línea de base; la segunda se realizó después de que las muestras se almacenaran en agua destilada a 37°C durante 24 horas. La profundidad de curado se calculó utilizando una relación de dureza inferior/ superior de las mediciones. El análisis estadístico se realizó utilizando el SPSS V23 y las pruebas de Shapiro-Wilk. Por último, se utilizó la prueba de Duncan para las comparaciones múltiples (p<0,05). VHN aumentó tras el procedimiento de precalentamiento en las resina Bulk-Fill, disminuyó en los GP. No hubo diferencias entre los valores de VHN de referencia y de 24 horas en SDR y GP. Después de 24 horas, mientras que el VHN de EST aumentó, el VHN de AFX disminuyó. No hubo diferencias entre los ratios de dureza de las muestras de AFX y EST (p<0,001) y los ratios de dureza fueron mayores que los de GP y SDR. Al comparar los valores de referencia y los de 24 horas, el VHN dependió del tipo de materiales. Se obtuvo una profundidad de curado suficiente en todos los grupos con un grosor de 2mm.

Effect of handling, time of use and photoactivation on the contamination of dental composite resins

This study evaluated the effect of contamination of composite resins (CRs) handled by undergraduate students during restorative procedures, varying the time (baseline, 30 days and 60 days) and experimental condition (before and after handling, contamination with saliva [positive control] and photoactivation). Eight CR tubes were randomly distributed at the dental clinic and the samples were organized into four groups: CR fragments collected before (GB) and after (GA) the restorative procedure; CR fragments contaminated with saliva (GS) and photoactivated (GP) both collected after the procedure. These 4 groups were evaluated in 3 different times: baseline (after sealing), 30 days and 60 days of use of the CR. Samples that had positive turbidity in Brain HeartInfusion (BHI) broth were sown in BHI and Sabouraud Dextrose (SB) agars for subsequent counting of Colony Forming Units (CFU mL-1). The results showed that the handling was responsible for increasing contamination (p < 0.05) at the baseline (GB [n = 0] and GA [n = 3]), as well as after 30 (GB [n = 1] and GA [n = 6]) and 60 (GB [n = 1] and GA [n = 5]) days of use. Photoactivation was responsible for the reduction for microorganisms in T0 and T60. Additionally, the time use and conservation did not influencethe contamination of CRs. Handling was responsible for the increase of contamination of CR, the photoactivation seems to reduce the number of viable microorganisms and the time of use seems not to potentiate the effect of tube contamination.

Evaluation of fracture strength and total void amount in composite restorations on endodontically treated teeth / Resistencia a la fractura y la cantidad total de burbujas en resinas compuestas de dientes tratados endodónticamente

ABSTRACT: The aim of the study was to investigate the fracture strength of different composite resins and the quantity of voids in conventional posterior composite, high- flow flowable composite, bulk-fill flowable composite, and fiber-reinforced composite. Forty-four caries-free, freshly extracted mandibular premolars were used for this study. Teeth were prepared for cavity and root canal treatment. Subsequently, root canal treatment was applied to the teeth and cavities in order to prepare them for restorations. The specimens were then divided into four groups: group-1: Estelite Posterior; group-2: Estelite Flow Quick High Flow; group-3: Estelite Bulk-fill Flow; group-4: everX Posterior. One specimen from each experimental group was examined using micro-CT to perform measurement of voids. The fracture strength values of high-flow flowable, bulk-fill flowable, fiber-reinforced, and conventional micro- hybrid composites were found to be similar (p=0.497). EverX Posterior showed the highest fracture strength values (841.1±149.4 N), followed by Estelite Bulk-fill Flow (822.8±170.8 N). Volume of voids (%) obtained from Micro-CT analysis revealed that restorations with high-flow liner or bulk-fill flowable exhibited more voids. The fiber-reinforced composite showed the lowest percentage volume of incorporating voids and the highest fracture strength results.

RESUMEN: El objetivo del estudio fue investigar la resistencia a la fractura de diferentes resinas compuestas y la cantidad de burbujas en resinas posteriores convencionales, resinas fluidas de alto flujo, resinas fluidas tipo bulk-fill y resinas reforzados con fibras. Cuarenta y cuatro premolares mandibulares libres de caries, recién extraídos, fueron usados para este estudio. Los dientes se prepararon para el tratamiento de conductos radiculares y las cavidades para prepararlos para las restauraciones. Los especímenes se dividieron en cuatro grupos: Grupo-1: Estelite Posterior; Grupo-2: Estelite Flow Quick High Flow; Grupo-3: Estelite Bulk-fill Flow; Grupo-4: everX Posterior. Un espécimen de cada grupo experimental fue examinado usando micro-CT para realizar la medición de las burbujas. Los valores de resistencia a la fractura de los compuestos de alto flujo, flujo de relleno, reforzados con fibra y microhíbridos convencionales fueron similares (p=0,497). EverX Posterior mostró los valores más altos de resistencia a la fractura (841,1±149,4 N), seguido de Estelite Bulk-fill Flow (822,8±170,8 N). El volumen de las burbujas (%) obtenido del análisis de Micro-TC reveló que las restauraciones con revestimiento de alto flujo o con flujo de relleno a granel presentaban más huecos. El compuesto reforzado con fibra mostró el menor porcentaje de volumen de incorporación de vacíos y los resultados más altos de resistencia a la fractura.

Contaminação microbiológica de resinas compostas utilizadas em uma clínica-escola de Odontologia / Microbiological contamination of composite resins used in a Dental school clinic

O objetivo desse estudofoi verificar a contaminação microbiológica deresinas compostas utilizadas em uma clínica-escola de Odontologia. Trata-se de uma pesquisa experimental/laboratorial, na qual foramcoletadas amostras de 10 bisnagas de resina composta, sendo uma delas o controle negativo. Porções de resina composta contidas no interior das bisnagas foram coletadas e mergulhadas em tubos de ensaio contendo caldo nutriente eposterior semeadura em placas e coloraçãopara caracterizar as colônias e observar bactérias e fungos. Todas as amostras apresentaram contaminação, inclusive o tubo contendo meio de cultura utilizado como controle de manuseio do experimento. Essas contaminações podem ter relação com as falhas dos meios de biossegurança empregados na clínica-escola e com os métodos de transporte e armazenamento das bisnagas de resina composta. Portanto, existe a necessidade de conscientização dos estudantese docentespara a adoção de medidas de biossegurança específicas para o manuseio das resinas compostas (AU).

The aim of this study was to verify the microbiological contamination in composite resins used at one Dental school clinic. This is an experimental/laboratory study, in which samples of 10 tubes of composite resin were collected, one of which was the negative control. Portions of composite resin inside the tubes were collected and dipped in test tubes containing nutrient broth for subsequent seeding on to plates and staining for the characterization of bacterial and fungal colonies. All samples revealed contamination, including the tube containing culture medium used as control for handling the experiment. These contaminations may be related to failures in biosafety measures employed in theDental school clinic and to the transport and storage methods for the tubes of composite resin. Therefore, it is necessary to raise awareness among students and teachers to adopt specific biosafety measures for the handling of composite resins (AU).

Avaliação do nível de conhecimento de acadêmicos de Odontologia sobre fotopolimerização / Evaluation of the knowledge of dental students on light curing

O sucesso clínico de materiais resinosos é dependente de uma adequada polimerização. Diversos materiais fotoativados são utilizados frequentemente nas clínicas-escola de Odontologia. O objetivo desse estudo foi avaliar o nível de conhecimento dos acadêmicos do 10º período de Odontologia do Centro Universitário Maurício de Nassau, Recife/PE,sobre fotopolimerização, por meio de questionário. Os dados foram tabulados e analisados por meio de estatísticas descritivas, teste Qui-quadrado de Pearson e teste Exato de Fischer, com nível de significância de 5% (p<0,05). Os resultados demonstram que 83,8%dos estudantesnão possuem fotopolimerizador, 72,9% não conhecem a potência do aparelho, 56,2% não sabem qual é a potência mínima ideal e apenas 8,5% sabem o nome do aparelho aferidor da irradiância / potência. Além disso, 48,5% não sabem o comprimento de onda ideal para fotoativação de resina composta e 69,2% desconhecemo tipo de aparelho que utilizam (monowaveou poliwave).Em relação ao tempo de fotopolimerização, 60,8% afirmaram utilizar20 segundos em resinas compostas convencionais e 38,5% utilizam por40 segundos em resinas compostas Bulk-fill. Embora 84,6% afirmem usar aparelhos fotopolimerizadores frequentemente, apenas 26,9% sabem a distância ideal da ponteira à restauração. Além disso, 51,5% relataram que fazem a limpeza e desinfecção com álcool 70GL e 45,4% usam barreira plástica. Nesse contexto, pode-se concluir que o nível do conhecimento dos acadêmicos em relação à fotopolimerização foi insatisfatório, exigindo uma abordagem e avaliaçãomais efetivaspara que os discentes tenham consciência da importância clínica deste procedimento e suas consequências (AU).

The clinical success of resin materials depends on adequate curing. Several light cured materials are frequently used in dental school clinics. This study aimed to assess the knowledge of students from the 10th period of Dentistry at Maurício de Nassau University Center, Recife/PE, about light curing, using a questionnaire. Data were tabulated and analyzed by descriptive statistics, Pearson chi-square test and Fisher exact test, at a significance level of 5% (p<0.05). The results show that 83.8% of studentsdo not have a light curing unit, 72.9% do not know the device power, 56.2% do not know the ideal minimum power and only 8.5% know the name of the device that measures the irradiance/power. Also, 48.5% do not know the ideal wavelength for light curing of composite resin and 69.2% do not know the type of device they use (monowave or polywave). Regarding the light curing time, 60.8% stated they used 20 seconds in conventional composite resins and 38.5% used 40 seconds in bulk-fill composite resins. Although 84.6% stated that they use light curing units frequently, only 26.9% know the ideal distance from the tip to the restoration. Additionally, 51.5% reported performing cleaning and disinfection with 70GL alcohol and 45.4% use a plastic barrier. In this context, it can be concluded that the knowledge of students regarding light curing was unsatisfactory, requiring a more effective approach and evaluation so that the students may be aware of the clinical importance of this procedure and its consequences (AU).

Discoloration of Bulk-Fill Versus Conventional Composites: A Spectrophotometric Evaluation / Decoloración de resinas Bulk vs resinas convencionales: Evaluación espectrofotométrica

ABSTRACT: Purpose: The purpose of this study was to evaluate the discoloration of a dual-cure bulk-fill (DCBF) and light-cure bulk-fill (LCBF) composites relative to conventional composites (CC) after water and coffee immersion. Methods: One- hundred disc-shaped specimens (8mm in diameter × 4mm thickness) were prepared using five commercially available composites (n=10); two LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), one DCBF (FU-Fill-upTM Coltene), and two CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Initial and final color readouts were measured with a spectrophotometer (Easyshade,Vita) according to the CIELAB color system. Statistical analyses were performed using 2-way ANOVA with Bonferroni adjustment to evaluate ΔE, ΔL, Δa, and Δb parameters (pFB≥XB>EQ≥CE in water immersion groups and XB>FB>EQ≥FU≥CE in coffee immersion groups. Conclusion: Within the limitations of this study, DCBF composite is more susceptible to intrinsic discoloration compared to LCBF and CC. However, DCBF exhibited lower extrinsic discoloration than LCBF and comparable with CC after coffee immersion. Depending on their chemical and structural compositions, composites will exhibit color change, which compromises the esthetic performance of composite restorations.

RESUMEN: Propósito: El propósito de este estudio fue evaluar la decoloración de resinas bulk de curado dual (DCBF) y bulk activadas por fotopolimerización (LCBF) en relación con las resinas convencionales (CC) después de la inmersión en agua y café. Métodos: Se prepararon cien muestras en forma de disco (8mm de diámetro × 4mm de espesor) utilizando cinco resinas compuestas disponibles comercialmente (n=10); dos LCBF (XB-X-trafil Voco, FB-FiltekTM Bulk Fill), un DCBF (FU-Fill-upTM Coltene) y dos CC (CE-Clearfil Majesty ES2, EQ-Estelite ΣQuick). Las lecturas de color inicial y final se midieron con un espectrofotómetro (Easyshade, Vita) de acuerdo con el sistema de color CIELAB. Los análisis estadísticos se realizaron utilizando ANOVA de 2 vías con ajuste de Bonferroni para evaluar los parámetros ΔE, ΔL, Δa y Δb (pFB≥XB>EQ≥CE en los grupos de inmersión en agua y XB>FB>EQ≥FU≥CE en los grupos de inmersión en café. Conclusión: Dentro de las limitaciones de este estudio, la resina DCBF es más susceptible a la decoloración intrínseca en comparación con LCBF y CC. Sin embargo, DCBF mostró una decoloración extrínseca más baja que LCBF y comparable con CC después de la inmersión en café. Dependiendo de sus composiciones químicas y estructurales, los composites mostrarán cambios de color, lo que compromete el desempeño estético de las restauraciones de resinas con el tiempo.

Effect of Surface Wetting Resin on the Color Stability and Microhardness of Esthetic Composites / Efecto de la resina humectante de superficies sobre la estabilidad del color y la microdureza de resinas compuestas estéticas

ABSTRACT: Objective: The aim of this study was to evaluate and compare the effects of the superficial application of two different modeling resins on the surface microhardness and discoloration of composite resins. Material and Methods: The present study used two different composites and modeling resins. The composites were placed in plastic molds. Subsequently, the modeling resins were applied on the surface of the two composite groups. The microhardness and color pertaining to all the groups were evaluated. The current study used the One-Way ANOVA and Kruskal Wallis tests, in order to perform the statistical evaluation (p<0.05). Results: The present study compared the microhardness pertaining to the groups and the highest microhardness values were observed in the Estelite Asteria group (none), whereas the lowest values were observed in the GC Essentia group (Ultradent). Moreover, the current study evaluated the color stability and the greatest discoloration was observed in the control group of the GC Essentia group, whereas the least discoloration was observed in the Estelite Asteria group that included the samples prepared using Ultradent Wetting Resin. Conclusions: The results of the present study demonstrated that the use of modeling resins, which facilitate the placement of composite resins, reduced the microhardness and discoloration of composite resins. The aforementioned effect can be attributed to the variations in the structure of the filling. However, further studies are warranted to support and verify the results of the current study.

RESUMEN: Objetivo: El objetivo del presente estudio fue evaluar y comparar los efectos de la aplicación superficial de dos resinas humectantes sobre la microdureza superficial y la decoloración de las resinas compuestas. Material y métodos: El presente estudio utilizó dos resinas humectantes y resinas de modelado diferentes. Las resinas compuestas se colocaron en moldes de plástico. Posteriormente, se aplicaron las resinas humectantes sobre la superficie de los dos grupos. Se evaluó la microdureza y el color de todos los grupos. El presente estudio utilizó las pruebas One-Way ANOVA y Kruskal Wallis, para realizar la evaluación estadística (p<0.05). Resultados: Los valores más altos de microdureza se observaron en el grupo Estelite Asteria, mientras que los menores valores se observaron en el grupo GC Essentia (Ultradent). La mayor decoloración se observó en el grupo control o el grupo GC Essentia, mientras que la menor decoloración se observó en el grupo Estelite Asteria con Ultradent Wetting Resin. Conclusiones: Los resultados del presente estudio demostraron que el uso de resinas humectantes, que facilitan la colocación de resinas compuestas, redujo la microdureza y decoloración de las resinas compuestas. El efecto mencionado anteriormente se puede atribuir a las variaciones en la estructura del relleno. Sin embargo, se necesitan más estudios para respaldar y verificar los resultados del presente estudio.

Bond Strength Evaluation of Bulk- fill Composites to Dentin Under Different Surface Treatments / Evaluación de la resistencia adhesiva de las resinas bulk-fill a la dentina con diferentes tratamientos de superficie

ABSTRACT: Purpose: The aim of this study is to compare the shear bond strength of three high-viscosity bulk-fill composite resins applied as single layers of 4mm thickness and of one microhybrid composite resin applied incrementally with a thickness of 2mm on dentin surfaces prepared with different surface preparation methods. Materials and Methods: A total of 132 caries-free human molars whose dentines had been exposed were used. Three groups, each containing 44 teeth, were formed. The acid group was etched with 32% phosphoric acid; laser group was etched with Er, Cr; YSGG laser and the control group was prepared with silicon carbid paper. Following the application of bonding agent, composite resin materials were applied on teeth using teflon moulds of 4x4mm. The samples were then subjected to shear bond strength tests. Two-way variance analysis and Tukey HSD multiple comparison test were applied on collected data. Results: There was a significant difference between surface treatment methods used regarding shear bond strength (P0.05). Conclusions: Laser etching of the dentin tissues is not as effective as acid etching. Bulk-fill composites had similar effects compared with conventional composite resins with regard to bonding strength. More in vitro studies supported with clinical data are required to investigate the performance of bulk-fill composites and laser.

RESUMEN: Propósito: El objetivo de este estudio es comparar la resistencia adhesiva al cizallamiento de tres resinas compuestas de relleno de alta viscosidad aplicadas como capas individuales de 4 mm de espesor y de una resina compuesta microhíbrida aplicada de forma incremental con un espesor de 2mm en superficies de dentina preparadas con diferentes métodos de preparación de la superficie. Materiales y métodos: Se utilizaron un total de 132 molares humanos sin caries cuyas dentinas habían sido expuestas. Se formaron tres grupos, cada uno con 44 dientes. El grupo ácido se grabó con ácido fosfórico al 32%; el grupo láser se grabó con Er, Cr; el láser YSGG y el grupo de control se preparó con papel de carburo de silicio. Después de la aplicación del agente adhesivo, se aplicaron materiales de resina compuesta en los dientes utilizando moldes de teflón de 4x4mm. A continuación, las muestras se sometieron a pruebas de resistencia adhesiva al cizallamiento. Se aplicó el análisis de varianza bidireccional y la prueba de comparación múltiple Tukey HSD a los datos recogidos. Resultados: Hubo una diferencia significativa entre los métodos de tratamiento de superficie utilizados en cuanto a la resistencia adhesiva al cizallamiento (P0,05). Conclusiones: El grabado láser de los tejidos de la dentina no es tan eficaz como el grabado al ácido. Las resinas de relleno bulk-fill tuvieron efectos similares en comparación con las resinas compuestas convencionales en lo que respecta a la rsistencia adhesiva. Se necesitan más estudios in vitro apoyados con datos clínicos para investigar el rendimiento de los composites de relleno y el láser.

Alternativas clínicas para el uso de composites Bulk-Fill compactables y fluidos: Reporte de un caso paso a paso / Clinical Alternatives for the Use of Compactable and Flowable Bulk-Fill Composites: A Step-by-Step Case Report

Resumen: El uso de resinas compuestas Bulk-Fill para la restauración de dientes posteriores ha sido masificada en los últimos años en las diferentes disciplinas clínicas de la Odontología. Esto puede deberse principalmente a la simplicidad en la técnica de aplicación de este material ya que requiere de su inserción dentro de la preparación cavitaria en espesores de resina compuesta de hasta 4-5mm, lográndose una reducción considerable de tiempo de trabajo clínico. Ante la existencia de diferentes viscosidades de este tipo de resinas compuestas, ciertas dificultades han sido identificadas ante la selección de cada material Bulk-Fill en relación a las posibles combinaciones que se pueden realizar entre las diferentes marcas disponibles en el mercado, inclusive cuando se usan junto con resinas compuestas convencionales. El objetivo del siguiente reporte de caso, es mostrar dos posibilidades clínicas paso a paso utilizando inicialmente resinas Bulk-Fill compactable en un solo incremento para un segundo molar superior, y luego, a través de la combinación de resinas compuestas Bulk-Fill del tipo fluidas, junto a resinas compuestas Bulk-Fill compactables y resinas compuestas convencionales de estratificación para esmaltes de alto índice de refracción para un primer molar superior.

Abstract: The use of Bulk-Fill composite resins to perform posterior restorations has been massified in recent years in the different clinical disciplines of Dentistry. This may be due mainly to the simplicity in the application technique of this material as it requires its insertion into the cavity preparation in 4-5mm of composite resin thickness, achieving a considerable reduction of clinical working time. Given the existence of different viscosities of this type of composite resins, certain difficulties have been identified before the selection of each Bulk-Fill material related to the possible combinations that can be made between the different brands available in the market, even when they are used with conventional composite resins. The purpose of the following case report, is to present two step-by-step clinical possibilities using initially, compactable Bulk-Fill composite resin in a single increment for the restoration of a second upper molar, and later, through the combination of Bulk-Fill flowable composite resin together with compactable Bulk-Fill composite resin and a high- refractive-index enamel-like conventional composite resin, for a first upper molar.

Identificação de resinas plásticas em embalagens presentes no comércio varejista de alimentos / Identification of plastic resins in packaging present in the food retail trade

O crescimento do mercado de embalagens e, concomitantemente, dos resíduos sólidos e descarte de embalagens de alimentos reforça a importância do símbolo de identificação do material no rótulo. O presente estudo teve como objetivo identificar as embalagens de alimentos encontradas no varejo com simbologia de identificação da resina e os principais materiais utilizados em suas embalagens. Foram avaliadas 283 embalagens de produtos das categorias chocolate, biscoito, frutas e legumes. A ausência da resina de identificação do material foi observada em 67% dos produtos. O principal material encontrado, no Grupo Inspeção Rótulo (GIR), foi o PP ­ utilizado em 55 das 94 embalagens. Os resíduos de embalagens de alimentos e de plástico são um problema ambiental tangível. No entanto, para observar melhoras é importante compartilhar a responsabilidade e unir esforços. Contudo, no âmbito da indústria de alimentos ainda é observado no mercado brasileiro uma deficiência na identificação dos diferentes materiais.(AU)

The growth of the packaging market and, at the same time, of solid waste and food packaging disposal reinforces the importance of the material identification symbol on the label. This study aimed to identify food packaging found in retail with resin identification symbology and the main materials used in their packaging. A total of 283 packages of products in the chocolate, biscuit, fruit and vegetable categories were evaluated. The absence of material identification resin was observed in 67% of the products. The main material found in the GIR group (Inspection Label Group) was PP ­ used in 55 of the 94 packages. Food packaging and plastic waste is a tangible environmental problem. However, to see improvements it is important to share responsibility and join efforts. However, within the food industry, a deficiency in the identification of different materials is still observed in the Brazilian market.(AU)

Forensic study of mechanical properties of dental restoration after burial in mangrove environment.

Conducting research in the field of forensic sciences with methodologies that simulate situations found in the day-to-day practice of a given field of expertise is relevant insofar as this approach can produce results that are as close as possible to reality. In this context, the present study provided situations based on burial in a mangrove environment to estimate the changes in the mechanical properties (Knoop microhardness, roughness and color) of dental restorations utilizing silver amalgam, composite resin and glass ionomer cement over the time of burial. The silver amalgam showed a significant increase in surface roughness and a reduction in Knoop microhardness. Composite resin showed a statistically significant increase in color variation, and the glass ionomer cement showed significant increases in color variation and Knoop microhardness. These results allowed us to conclude that teeth restored with silver amalgam, composite resin and glass ionomer cement submitted to burial in mangrove environments produce different changes in surface roughness, Knoop microhardness and color properties depending on the time of burial to which the victims were submitted. These proprieties could help the forensic sciences to estimate time intervals for burial in mangrove environments.

The effects of intrinsic and extrinsic acids on nanofilled and bulk fill resin composites: Roughness, surface hardness, and scanning electron microscopy analysis.

The objective of this study was to examine the effects of extrinsic or intrinsic acids on nanofilled and bulk fill resin materials in vitro. A total of 90 disks were prepared using dental restorative material (Filtek Z350XT, GrandioSO, Filtek Bulk Fill, X-tra fil). Thirty disks of each material were sub-divided into three groups (n = 10) that were immersed for 7 days in deionized water (DW), 5% citric acid (CA-pH 2.1), or 0.1% hydrochloric acid (HCl-pH = 1.2). Surface hardness and roughness (stylus profilometer by Ra parameter) analysis were performed before and after immersion. Morphological changes were evaluated by scanning electron microscopy. The data were analyzed by two-way ANOVA and Tukey's test (α = 0.05). All tested materials did not show significant differences in the effects of the DW, CA, or HCl solutions on surface roughness (p = .368). Likewise, the hardness loss was not affected by the solutions tested (p = .646), but there was a difference in the resin type (p = .002). Filtek Bulk Fill resin hardness was less affected, while Filtek Z350XT and GrandioSO presented the most hardness loss after 7 days of solution immersion. In terms of this experimental study, the results demonstrate the effectiveness of the mechanical properties (roughness and hardness surface) of nanofilled and bulk fill resin materials to resist erosion from extrinsic and intrinsic acids, therefore being potential candidates for dental applications.

Efeitos do uso de produtos clareadores de autoaplicação sobre a superfície de uma resina composta nanoparticulada / The effects of over-the-counter bleaching products on the surface of nanofilled composite

Objetivo: Avaliar a alteração da rugosidade superficial de uma resina composta nanoparticulada (Filtek Z350 XT ® ) após o uso de produtos clareadores de autoaplicação contento baixa concentração de peróxido de hidrogênio. Métodos: Para isto, foram confeccionados 30 corpos de prova deste material, divididos aleatoriamente em 3 grupos com 10 amostras cada, da seguinte forma: G1 (grupo controle) no qual as amostras não foram submetidas à ação de nenhum produto clareador; G2, realização de procedimento clareador com peróxido de hidrogênio a 10% (Crest 3D White Professional Effects Whitestrips ® ) em 2 aplicações de 30 minutos, por 10 dias consecutivos; e G3, tratamento com peróxido de hidrogênio a 7,7% (pincel Pretty Smile ® ) com o mesmo número de aplicações, tempo e dias do G2. Após este período cada corpo de prova foi analisado no rugosímetro Surftest SJ-301, para determinar a sua rugosidade superficial média. Estes dados foram então submetidos à análise estatística por meio da análise de variância (ANOVA) e teste de Tukey, nível de significância de 5% para comparações múltiplas. Resultados: Ao final do experimento, houve diferenças estatísticas significantes entre o grupo controle (G1) e os demais grupos (G2 e G3), com p < 0,05. Porém, quando analisados apenas os grupos submetidos ao clareamento com o peróxido de hidrogênio em diferentes concentrações (G2 e G3), não foi encontrada diferença significativa (p > 0,05). Conclusão: Após 10 dias, os produtos clareadores testados determinaram aumento significativo nos valores de rugosidade superficial média da resina composta nanoparticulada.

Aim: Tod evaluate the change in surface roughness of a nanoparticulate composite resin (Filtek Z350 XT ® ) after using over-the-counter bleaching products, containing a low concentration of hydrogen peroxide. Methods: For this, 30 specimens of this material were made, randomly divided into 3 groups with 10 samples each, as follows: G1 (control group) in which the samples were not subjected to the action of any bleaching product; G2, performing a bleaching procedure with 10% hydrogen peroxide (Crest 3D White Professional Effects Whitestrips ® ), in 2 applications of 30 minutes, for 10 consecutive days; and G3, treatment with 7.7% hydrogen peroxide (Pretty Smile ® ), with the same number of applications, time, and days as G2. After this period, each specimen was analyzed, using the Surftest SJ-301, to determine its average surface roughness. These data were then subjected to statistical analysis through analysis of variance (ANOVA) and Tukey's Test, with a significance level of 5% for multiple comparisons. Results: Statistically significant differences were found between the control group (G1) and the other groups (G2 and G3), with p < 0.05. However, when analyzing only the groups submitted to bleaching agents with hydrogen peroxide in different concentrations (G2 and G3), no significant difference was found (p > 0.05). Conclusions: After 10 days, the bleaching products tested in this study determined a significant increase in the average surface roughness values of the nanoparticulate composite resin.

Fluoride Release of Giomer and Resin Based Fissure Sealants / Liberación de flúor de sellantes de fosas y fisuras a base de resina y/o ionómero

ABSTRACT Fissure sealants are applied to teeth to prevent caries development. The presence of the fissure sealant creates a protective barrier, which prevents plaque accumulation to the pits and fissure. They have a significant role in preventing pit and fissure caries. The aim of this study was to evaluate the time-dependent fluoride ion release of giomer- and resin-based fissure sealants. Fissure sealants were divided into 4 groups: BeautiSealant (Shofu, Japan), Clinpro Sealant (3M ESPE, USA), Helioseal F (Ivoclar Vivadent, Liechtenstein), Fissurit F (Voco, Germany). Disk shaped samples were prepared for each sealant material tested, and they were transferred into polyethylene vials containing 5 ml of deionized water. Fluoride ion diffusion was determined on days 1,2,3,7,14,21, and 28 (n=7). The fluoride concentration in these samples was analyzed using a pre-calibrated spectrophotometer in parts per million (ppm). These experiments were performed in triplicates at room temperature. ANOVA and Tukey's HSD test were used for statistical analysis. BeautiSealant was released the highest amount of fluoride on day 1 (5.33 ppm), followed by a sudden decrease on the day 2 (2.17ppm). The burst effect was observed only in this group. Clinpro Sealant, Fissurit F and HelioSeal F groups presented fluoride release of 2.69, 2.94 and 2.91 ppm on the first day, respectively, without a significant difference (p>0.05). After the first week, a constant fluoride release level has been reached. The fluoride release for the three resin-based fissure sealants was slightly lower than that for the giomer-based. After the first week, materials exhibited no significant difference and reached a plateau. The usage of a high and prolonged fluoride-releasing fissure sealant material should be considered by clinicians, particularly in patients with caries risk.

RESUMEN Los sellantes de fosas y fisuras se utilizan con el objetivo de prevenir el desarrollo de caries. La presencia del sellante crea una barrera protectora, que evita la acumulación de placa en las fosas y fisuras. Tienen un papel importante en la prevención de la caries. El objetivo de este estudio fue evaluar la liberación de iones fluoruro de los sellantes de fosas y fisuras a base de Ionómeros y resinas. Los sellantes de fosas y fisuras se dividieron en 4 grupos: BeautiSealant (Shofu, Japón), Clinpro Sealant (3M ESPE, EE. UU.), Helioseal F (Ivoclar Vivadent, Liechtenstein), Fissurit F (Voco, Alemania). Se prepararon muestras en forma de disco para cada material, y se transfirieron a viales de polietileno que contenían 5 ml de agua desionizada. La difusión de iones fluoruro se determinó en los días 1,2,3,7,14,21 y 28 (n=7). La concentración de fluoruro en estas muestras se analizó utilizando un espectrofotómetro precalibrado en partes por millón (ppm). Estos experimentos se realizaron por triplicado a temperatura ambiente. ANOVA y la prueba de HSD de Tukey se utilizaron para el análisis estadístico. BeautiSealant liberó la mayor cantidad de fluoruro en el día 1 (5.33 ppm), seguido por una disminución repentina en el día 2 (2.17ppm). Los grupos Clinpro Sealant, Fissurit F y HelioSeal F presentaron una liberación de fluoruro de 2.69, 2.94 y 2.91 ppm el primer día, respectivamente, sin una diferencia significativa (p> 0.05). Posterior a la primera semana, fue alcanzado un nivel constante de liberación de fluoruro. La liberación de flúor para los tres sellantes de fosas y fisuras a base de resina fue ligeramente inferior a la de los Ionómeros. Después de la primera semana, los materiales no mostraron diferencias significativas. Los odontólogos deben considerar el uso de un material sellante de fosas y fisuras que promueva la liberación de flúor a lo largo del tiempo, especialmente en pacientes con riesgo de caries.